Is this a Smoker vs. Thumper debate or a bigger vs. smaller debate?
Upfront, I primarily ride tight woods sections connected by large grass tracts (Intermediate and Over 30X years ago). I've raced everything from a 125 smoker to the old KTM 525 on our local cross country circuit. Recently I returned to riding when I bought a used XR250R for my son. Went riding with a buddy and his RMZ450 a few weeks ago. He was really impressed I could maintain a such quick pace on such an "old fashioned" machine. I was impressed with how much work it was to ride that bull of his. While passing bigger bikes on long grass track sections would be a chore on a smaller 4 stroke, there is something to be said for the 'less is more' philosophy.
On that topic, I was told recently 250F bikes will often set faster lap times in Supercross than their larger siblings. Begs the question, what's more important: a fast bike or a bike you can ride fast (consistently)?